The present invention relates to a soft magnetic alloy suitable for magnetic head cores, thin film inductors, thin film transformers, switching elements, etc., and to a plane magnetic element using such a soft magnetic alloy.
As a result of the recent miniaturization and enhancement in performance of magnetic elements, there is a demand for a soft magnetic material exhibiting a high magnetic permeability in the frequency range of several hundred MHz or more, and, in particular, one having a high saturation magnetic flux density of 5 kG or more, a high specific resistance, and a low coercive force. Above all, there is a demand for a soft magnetic material having a high specific resistance as a material for transformers.
Fe or alloys containing Fe as a main component are widely known as magnetic materials having a high saturation magnetic flux density. However, when formed into a magnetic film by a film formation technique, such as sputtering, such an alloy exhibits a high coercive force and a low specific resistance although it has a high saturation magnetic flux density. Thus, it is difficult to obtain satisfactory soft magnetic properties from such an alloy.
One of the causes for the reduction in magnetic permeability in the high frequency range, is the loss due to the generation of an eddy current. To prevent the generation of an eddy current, a reduction in film thickness and an increase in thin film resistivity are required.
However, it is extremely difficult to achieve an increase in specific resistance without any deterioration in magnetic properties. The specific resistance of a soft magnetic thin film made of an alloy, such as sendust, is as small as tens .mu..OMEGA..cm. What is required is a soft magnetic alloy which has an increased specific resistance, and yet ensures a saturation magnetic flux density of at least 0.5 T.
Further, when realizing an alloy in the form of a thin film, it is still more difficult to obtain satisfactory soft magnetic properties, due to the influences of the generation of magnetostriction, etc.
The present invention has been made with a view toward solving the above problems. It is accordingly an object of the present invention to provide a soft magnetic alloy having a high specific resistance as a magnetic material for use in the high frequency range, etc., and a plane magnetic element using such a soft magnetic alloy.